Friction-speed characteristics of full journal bearings made from Cu6Sn10Pb and Cu6Sn with and without phosphorus were determined, using a straight mineral white oil as lubricant. It was found that the bearings run in smoothly if the bearing-operating temperature remains below Tt, i.e., the transition temperature for effective boundary lubrication. At bearing-operating temperatures above Tt, boundary lubrication fails, and wear and surface deterioration interfere with the formation of a hydrodynamic lubricant film, a consequence being that phosphorus-free alloys behave better than phosphorus-containing alloys. This effect was also found with a crankcase oil of HD SAE 20W type.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE International Lubrication Conference held in New York City, October 9–12, 1972